<h4>Tool</h4><table border="0"><tr><td valign="top"><b>Name</b></td><td valign="top">LS Factor</td></tr><tr><td valign="top"><b>ID</b></td><td valign="top">22</td></tr><tr><td valign="top"><b>Author</b></td><td valign="top">O.Conrad (c) 2003</td></tr><tr><td valign="top"><b>Specification</b></td><td valign="top">grid</td></tr></table><hr><h4>Description</h4>Calculation of slope length (LS) factor as used by the Universal Soil Loss Equation (USLE), based on slope and specific catchment area (SCA, as substitute for slope length). 
References:

Boehner, J., Selige, T. (2006):
Spatial Prediction of Soil Attributes Using Terrain Analysis and Climate Regionalisation'
In: Boehner, J., McCloy, K.R., Strobl, J.: 'SAGA - Analysis and Modelling Applications', Goettinger Geographische Abhandlungen, Vol.115, p.13-27

Desmet & Govers (1996):
'A GIS Procedure for Automatically Calculating the USLE LS Factor on Topographically Complex Landscape Units'
Journal of Soil and Water Conservation, 51(5):427.433

Kinnell, P.I.A. (2005):
'Alternative Approaches for Determining the USLE-M Slope Length Factor for Grid Cells.'
<a href="http://soil.scijournals.org/cgi/content/full/69/3/674">http://soil.scijournals.org/cgi/content/full/69/3/674</a>

Moore, I.D., Grayson, R.B., Ladson, A.R. (1991):
'Digital terrain modelling: a review of hydrogical, geomorphological, and biological applications'
Hydrological Processes, Vol.5, No.1

Wischmeier, W.H., Smith, D.D. (1978):
'Predicting rainfall erosion losses - A guide to conservation planning'
Agriculture Handbook No. 537: US Department of Agriculture, Washington DC.
<hr><h4>Parameters</h4><table border="1" width="100%" valign="top" cellpadding="5" rules="all"><tr><th>Name</th><th>Type</th><th>Identifier</th><th>Description</th><th>Constraints</th></tr>
<tr><th colspan="5">Input</th></tr><tr><td>Slope </td><td>Grid (input)</td><td>SLOPE</td><td></td><td></td></tr><tr><td>Catchment Area </td><td>Grid (input)</td><td>AREA</td><td></td><td></td></tr><tr><th colspan="5">Output</th></tr><tr><td>LS Factor</td><td>Grid (output)</td><td>LS</td><td></td><td></td></tr><tr><th colspan="5">Options</th></tr><tr><td>Area to Length Conversion</td><td>Choice</td><td>CONV</td><td>Derivation of slope lengths from catchment areas. These are rough approximations! Applies not to Desmet & Govers' method.</td><td>Available Choices:
[0] no conversion (areas already given as specific catchment area)
[1] 1 / cell size (specific catchment area)
[2] square root (catchment length)
Default: 0</td></tr><tr><td>Method (LS)</td><td>Choice</td><td>METHOD</td><td></td><td>Available Choices:
[0] Moore et al. 1991
[1] Desmet & Govers 1996
[2] Boehner & Selige 2006
Default: 0</td></tr><tr><td>Rill/Interrill Erosivity</td><td>Floating point</td><td>EROSIVITY</td><td></td><td>Minimum: 0.000000
Default: 1.000000</td></tr><tr><td>Stability</td><td>Choice</td><td>STABILITY</td><td></td><td>Available Choices:
[0] stable
[1] instable (thawing)
Default: 0</td></tr></table>